A conventional in the ear (ITE) or completely-in-the-canal (CIC) hearing aid has a housing that is custom made to individually fit the user's ear canal. The hearing aid components, e.g. electronics, microphone, receiver, battery, etc., are contained in the housing which is closed by a faceplate at the end pointing away from the ear canal. In order to reduce occlusion, a so-called vent, i.e. a ventilation channel, is provided for communication between an opening in the faceplate and the user's ear canal. The vent may be drilled through the housing or shell, or a pipe or tube extending within the hearing aid and connecting an opening in the faceplate with an opening at the opposite end of the housing may constitute the vent. The effectiveness of the vent is increased by increasing the cross-section and decreasing the length of the vent channel.
Behind-the-ear (BTE) hearing aids in which a sound tube conducts sound generated by the receiver of the hearing aid into the ear canal are also well known in the art. In order to position the sound tube securely and comfortably in the ear canal, an earpiece is provided for insertion into the ear canal of the user.
Typically, the ITE or CIC housing or the BTE earpiece is individually custom manufactured to fit precisely in the ear canal of the user without causing pain to the user while still retaining the housing or earpiece securely in place in the ear canal preventing the earpiece from falling out of the ear irrespective of movements of the user, such as chewing or yawning, and also avoiding acoustical feedback generating unpleasant and annoying whistling or howling. The custom made earpiece adds to the cost of the hearing aid and the time needed to fit the hearing aid.
Typically, customized hearing aids are made from solid materials to secure retention and tightness. These hearing aids are placed completely or partially in the ear canal. Since the walls of the ear canal are moving when the jaws move for instance when chewing, the placement of such solid hearing aids in the ear canal can be associated with discomfort for the user.
Several approaches to eliminate this discomfort have been tried, one such approach is to make the canal portion of the device in a soft material, e.g. as disclosed in WO 02/03757 A1. Such devices are complicated to manufacture and will only offer limited venting.
In WO 2004/010734, a canal hearing device is disclosed having a dual acoustic seal system for preventing feedback while minimizing occlusion effects. The two-part device comprises a main module and an elongated tubular insert for conducting sound to the eardrum and sealing within the bony region of the ear canal. The main module is positioned in the cartilaginous portion of the ear canal. The tubular insert comprises a sound conduction tube and a cylindrically hollow primary seal medially positioned in the bony region. The device also comprises a secondary seal laterally positioned in the cartilaginous region.
WO 01/08443 discloses a one-size-fits-all hearing aid, which is adapted to fit into either ear of an ear canal of a user to a depth proximal to the tympanic membrane. The hearing aid is comprised of two half shells joined together to house the hearing aid components. The joined shells secure a flexible tip at the distal end of the shell.
According to a first aspect of some embodiments, a set of hearing instrument housing parts is provided, comprising
a trunk part shaped for accommodation in the ear canal of a user and configured for interconnection with
a left ear connector configured to be attached to the trunk part and to be attached to a first end of an elongate member having an opposite second free end in such a way that the elongate member forms an angle with the longitudinal extension of the trunk part, when operatively interconnected with the trunk part, the angle being suitable for use in the left ear of the user, and
a right ear connector configured to be attached to the trunk part and to be attached to the first end of the elongate member having the opposite second free in such a way that the elongate member forms an angle with the longitudinal extension of the trunk part, when operatively interconnected with the trunk part, the angle being suitable for use in the right ear of the user,
the elongate member being configured for interconnection with a selected one of the left ear connector and the right ear connector and for positioning outside the ear canal in the pinna for retention of the trunk part in the ear canal.
Retention of the hearing instrument in the proper place is important. Jaw movements can exert outward forces on parts of the hearing instrument housing that reside in the ear canal during use. Preferably, the elongate member has sufficient resilience to counteract this force thereby securing parts of the hearing instrument housing residing in the ear canal from outward motion.
The elongate member may be adapted to be positioned in the pinna of the user around the circumference of the conchae abutting the antihelix and at least partly covered by the antihelix for retainment of its position.
The elongate member may be preformed during manufacture, preferably into an arched shape with a curvature slightly larger than the curvature of the antihelix, for easy fitting of the elongate member into its intended position in the pinna.
The elongate member may be resilient for assisting in retaining the trunk part of the housing in the ear canal of the user so that the trunk part of the housing remains securely in place in the ear canal without falling out of the ear irrespective of movements of the user, such as smiling, chewing or yawning. Retention is provided without causing pain to the user.
Preferably, the elongate member is resilient in a direction perpendicular to its longitudinal extension thereby providing further capability of retention of the trunk part of the housing in the ear canal of the user. During positioning of the trunk part of the housing in its intended position in the ear canal of the user, the transverse resilience of the elongate member facilitates insertion of the trunk part of the housing into the ear canal of the user.
The elongate member may further be adapted to abut part of the concha at the antitragus when the trunk part of the housing has been inserted in the ear canal thereby applying a force to the trunk part of the housing towards an upper part of the ear canal and thereby retaining the trunk part of the housing in a position in which the trunk part of the housing is pressed against the wall of the upper part of the ear canal. The upper part of the ear canal remains relatively unaffected during jaw movement so that parts of the housing resting against the upper part of the ear canal wall are subjected to the least possible outward moving forces during jaw movement.
Preferably, the elongate member is adapted to abut the antihelix and extend at least to the inferior crus of the antihelix when the trunk part of the housing is positioned in the ear canal of the user.
More preferred the elongate member is adapted for positioning of the second end at the cimba concha below the triangular fossa of the ear of the user when the trunk part of the housing is positioned in the ear canal of the user.
The elongate member may be adapted for accommodation of a microphone. For example, the elongate member may be adapted for accommodation of the microphone at its second end. The elongate member may have a larger cross-section at its second end accommodating the microphone than a remaining part of the elongate member extending therefrom and towards the first end.
Positioning of the microphone of a hearing aid at the second end of the elongate member provides a large distance between the microphone and the hearing aid receiver thereby minimizing feedback.
Feedback limits the maximum gain available to the user of the hearing aid. Feedback refers to the amplified signal returning to a hearing aid input. The feedback path may be an acoustic feedback path of sound propagating from the receiver along a path outside the hearing instrument to the microphone. This phenomenon, which is also known as acoustical feedback, occurs e.g. when a hearing instrument housing does not completely fit the wearer's ear, or in the case of a housing comprising a so-called vent, i.e. a canal or opening for e.g. ventilation purposes. In both examples, sound may “leak” from the receiver to the microphone and thereby cause feedback.
Additionally, inductive feedback may occur in the hearing aid, for example via a telecoil of the hearing aid coupling a magnetic field generated by the receiver into the telecoil thereby generating a hearing aid input signal.
Oscillation may arise when the attenuation provided by the feedback path is smaller than the hearing aid gain. A large distance between the microphone and the receiver alleviates this problem.
However, feedback in a hearing instrument may also occur internally since sound can be transmitted from the receiver to the microphone via a path inside the hearing instrument housing. Such transmission may be airborne or caused by mechanical vibrations in the hearing instrument housing or some of the components within the hearing instrument. In the latter case, vibrations in the receiver are transmitted to other parts of the hearing instrument, e.g. via the receiver mounting(s). For this reason, the receiver is for example not fixed but flexibly mounted within some state-of-the-art hearing aids of the ITE-type (In-The-Ear), whereby transmission of vibrations from the receiver to other parts of the device is reduced.
While the problem of external feedback limits the maximum gain available in a hearing aid while in use by a hearing impaired wearer, the problem of internal feedback has its main implications in the production process of hearing instruments, where it is today a very time-consuming manual procedure to mount and/or place receiver and microphone(s) in the devices in such a way that internal feedback is minimised.
The continuing minimisation of the size of a hearing aid makes it more and more critical to accurately position the receiver in the hearing aid housing during manufacture or service so that internal feedback is kept at a minimum. This also makes the hearing aid less robust against bumps or impacts against the surroundings that may occur during use of the hearing aid, since a slight displacement of the receiver may cause sufficient internal feedback to significantly reduce the maximum gain made available to the user without howling or whistling of the hearing instrument.
Thus, the long distance provided between the receiver and the microphone in the present housing makes positioning of the receiver easy to perform during manufacture or service and robust during use without reducing the maximum gain made available to the user of the hearing instrument.
Further, the long distance makes it possible to mount the receiver in close contact with the hearing instrument housing, since the internal mechanical and/or acoustical feedback will be suppressed due to the long distance between receiver and microphone. Thus, the previously required suspension of the receiver in resilient suspensions within the hearing instrument is no longer necessary. The receiver may be snugly fitted within the hearing instrument housing, e.g. within a compartment of the hearing instrument housing having mechanical support elements abutting the hearing instrument when mounted and keeping the receiver in a specific position during use. The mounting of the receiver is thereby made robust against mechanical bumps or impacts that the hearing instrument will experience during transport or use. Further, the manufacture of the hearing instrument is simplified and less costly and makes it easy to calibrate.
Further, absence of specific receiver mountings makes more volume available inside the hearing instrument housing for a larger receiver so that the present hearing instrument housing is capable of accommodating a larger receiver than can be accommodated inside similar sized conventional hearing instrument housings. Thus, the present hearing instrument housing with a microphone in the elongate member is capable of providing a larger gain than provided by similar sized conventional hearing instrument housings.
The internal feedback signal path between the microphone and the receiver may comprise a mechanical connection, an acoustical connection, or a combined mechanical and acoustical connection.
Here, the term acoustical refers to sound propagating as pressure waves in a gas, such as ordinary air within the hearing aid, while the term mechanical refers to sound propagating as vibrations through solid materials, such as the hearing instrument housing, receiver/microphone mountings etc.
Thus, the internal feedback signal path may comprise mechanical elements in the hearing aid, such as receiver, microphone, mountings and housing, and in some cases, also an acoustical element, such as air within the hearing instrument housing.
The external feedback signal path is typically an acoustic path between the microphone and the receiver, i.e. an external feedback signal propagates through air surrounding the hearing aid.
As further described below, electronic feedback suppression may also be provided in the hearing instrument according to some embodiments.
The elongate member may accommodate further electrical hearing instrument components.
In an elongate member with a microphone at the second end of the elongate member, the elongate member is preferably substantially rigid in the direction of its longitudinal extension so that electrical conductors residing in the elongate member are protected against breaking.
With a microphone in the elongate member at its second end, localisation is substantially maintained when the microphone is positioned at a location within the pinna wherein the microphone receives a sound signal that allows the user to perceive the direction towards a sound source. Then, the sound signal based on which the user is capable of perceiving direction is transmitted to the ear drum of the user by the hearing aid. For example, sense of direction may be substantially maintained when the microphone is positioned at the cimba concha below the triangular fossa in the pinna.
Two microphones may be accommodated at the second end of the elongate member for provision of noise suppression and/or further directionality.
The elongate member and the trunk part preferably form separate units that are manufactured in separate pieces. The trunk part of the housing and the elongate member may be interconnected mechanically and possibly electrically via the left ear connector or the right ear connector during manufacture of the hearing instrument, or they may be interconnected at a later stage, e.g. by the dispenser during fitting of the hearing instrument to a user.
The elongate member according to some embodiments is preferably manufactured in a number of standard sizes to fit the human anatomy of the pinna of most users. In this way, the manufacturing cost is lowered as compared to the manufacturing cost of customized elongate members.
The present hearing instrument housing is preferably manufactured in a number of standard sizes to fit the human anatomy of the ear canal of most users. In this way, the manufacturing cost is lowered as compared to the manufacturing cost of customized housings. Various standard sizes may also be provided for accommodation of batteries of different sizes, and various standard sizes may be provided for accommodation of receivers of different sizes.
In a preferred embodiment, the elongate member is removably interconnected with the trunk part of the housing so that a large number of different models of the hearing aid may be provided by combining elongate members of different standard sizes with a standard sized trunk part possibly selected from a set of differently sized trunk parts.
The left ear connector may be configured to be removably attached to the trunk part. Further, the right ear connector may be configured to be removably attached to the trunk part.
The housing may comprise a battery door providing access to a battery compartment for accommodation of a non-rechargeable battery. The elongate member may be attached to the battery door and the battery door may be removably attached to the trunk part of the housing with the right ear connector or the left ear connector included in the battery door for removal of the elongate member from the trunk part together with the battery door.
The battery door with the elongate member may be manufactured in one shape suitable for the right ear and another shape suitable for the left ear. In the shape suitable for the right ear, the elongate member extends from the battery door at a certain angle with relation to the battery door suitable for positioning of the elongate member in the pinna of the right ear when the trunk part has been inserted into the right ear canal of the user. In the shape suitable for the left ear, the elongate member extends from the battery door at a certain angle with relation to the battery door suitable for positioning of the elongate member in the pinna of the left ear when the trunk part has been inserted into the left ear canal of the user.
The connector may further be adapted for making electrical contact with a signal line in the elongate member when the battery door is attached to the housing.
Preferably, the hearing instrument housing provides an open solution. In accordance with hearing aid terminology, a hearing instrument with a housing that does not obstruct the ear canal when the housing is positioned in its intended operational position in the ear canal; is categorized “an open solution”. The term “open solution” is used because of the passageway between a part of the ear canal wall and a part of the housing allowing sound waves to escape from behind the housing between the ear drum and the housing through the passageway to the surroundings of the user. With an open solution, the occlusion effect is diminished and preferably substantially eliminated.
A user being fitted with a conventional hearing aid experiences an altered perception of his or her voice mainly due to occlusion of the ear canal by the housing or earpiece. The user typically describes the sound of his or her voice in one of the following terms: “My voice echoes”, “My voice sounds hollow” or “I sound like I'm talking in a barrel”.
Sounds originating from the vocal tract (throat and mouth) are transmitted into the ear canal through the cartilaginous tissue between these cavities and the outer portion of the ear canal.
When nothing is positioned in the ear canal, most of this predominantly low frequency sound simply escapes from the ear canal. However, when the ear canal is blocked these bone-conducted sounds cannot escape from the ear canal. The result is a build-up of high sound pressure levels in the residual ear canal volume. This increase in low frequency sound pressure is audible and will cause them to hear their own voice as loud and boomy. Change in perception of own voice is the most dominant occlusion related complaint, but not the only one. Other occlusion related problems include too much amplification at low frequencies for hearing aid users with good low frequency hearing, reduced speech intelligibility, poorer localization, physical discomfort and increased risk of external ear irritation and infection. Hearing aid users do not adapt to occlusion and the occlusion effect has been cited by as many as 27% of hearing aid wearers as a reason for dissatisfaction with their hearing aids. This emphasizes the need for alleviating or, even better, eliminating the occlusion effect.
Thus, preferably, the trunk part and possible further parts of the housing residing in the ear canal during use have a cross-section that is smaller than the cross-section of the ear canal so that occlusion substantially does not occur. When the housing is inserted into the user's ear canal, the smaller cross-section of the trunk part and possible further parts of the housing allows communication between the ear canal between the eardrum and the housing and the surroundings for prevention of occlusion.
The trunk part is preferably substantially straight along its longitudinal extension.
Preferably, the trunk part has a substantially rectangular cross-section perpendicular to its longitudinal extension.
Preferably, the trunk part has a substantially rectangular cross-section extending in parallel with its longitudinal extension.
The trunk part may further comprise a connector configured for making electrical contact with a signal line in the elongate member when the elongate member is attached to the trunk part.
The size and shape of the ear canal vary among individuals. Typically, the ear canal is approximately 26 mm long and 7 mm in diameter. In most cases, the ear canal bends backwards and slightly upward in the medial direction, i.e. in the direction from the entrance of the ear canal towards the ear drum. Thus, a right tip part of the hearing instrument housing fitting into the right ear canal of the user is preferably provided that forms an angle towards the left with relation to the longitudinal extension of the trunk part when seen from above in the medial direction of the ear canal. Further, a left tip part fitting into the left ear canal of the user is preferably provided that forms an angle towards the right with relation to the longitudinal extension of the trunk part when seen from above in the medial direction of the ear canal. Individuals with a straight ear canal requiring a straight tip part are rare.
The set of hearing instrument housing parts may further comprise
a right tip part that forms an angle with relation to the longitudinal extension of the trunk part when operatively interconnected with the trunk part, facilitating accommodation in the right ear canal of the user of a hearing instrument housing comprising the interconnected trunk part and right tip part, and
a left tip part that forms an angle with relation to the longitudinal extension of the trunk part when operatively interconnected with the trunk part, facilitating accommodation in the left ear canal of the user of a hearing instrument housing comprising the interconnected trunk part and left tip part,
the trunk part being further configured for interconnection with a selected one of the left tip part and the right tip part.
The set of hearing instrument housing parts may further comprise a straight tip part that is straight and extends along the longitudinal extension of the trunk part when operatively interconnected with the trunk part.
Tip parts may be manufactured in a number of standard sizes and shapes, e.g. in a number of angles formed with relation to the longitudinal extension of the trunk part when assembled with the trunk part, and in a number of lengths, widths and heights, and in a number of angular depths, i.e. distances from the interconnection between the tip part and the trunk part to the bend of the tip part, etc., for accommodation in respective ear canals of different sizes and with bends occurring at different depths in the ear canal and with different bending angles.
The tip part of the housing may be flexible for variation of the angle for increased wearing comfort.
The tip part may be customized to individually fit the user's ear canal without causing pain to the user while still retaining the housing securely in place in the ear canal preventing the housing from falling out of the ear irrespective of movements of the user, such as smiling, chewing or yawning.
Since the customized tip part accurately fits the shape of the ear canal, the internal volume of the tip is defined by the shape of the ear canal at the intended position of the tip part in the ear canal. Thus, in the intended position, the largest possible volume is provided for accommodation of the receiver whereby insertion into a narrower ear canal than would have been possible with a standard sized tip part is made possible. Alternatively, accommodation of a larger receiver than the receiver in a standard sized tip part may be possible in a customized tip part. Therefore, the customized tip part facilitates larger sound amplification. This is further supported by the tight fitting of the customized tip part to the ear canal wall preventing sound pressure leakage around the tip part and thus, making formation of large sound pressures possible. Further, the tight fit suppresses external feedback.
Additionally, conventional customized CIC or ITE hearing aid housings have a large contact surface with the surface of the ear canal when mounted in the ear canal. Most of the surface of the housing of a conventional customized CIC or ITE hearing aid accurately fits the ear canal of a user and therefore, the surface of the housing is in close contact with the ear canal and sometimes part of the concha as well. This large contact area of conventional CIC or ITE hearing aids leads to several inconveniences for the user. For example, humidity cannot escape to the surroundings in a normal way, since the humidity is trapped by the tightly fitted housing. The trapped humidity is inconvenient in it self, but typically also leads to increased temperatures and increased formation of bacteria on the skin surface of the ear canal, which again may lead to infections that have to be treated by a doctor.
Thus, by provision of a hearing instrument housing with a standard sized trunk part and a customized tip part, a hearing instrument housing is provided wherein only the tip part fits sealingly with the ear canal wall and thus, the provided housing has a very small area of contact with the skin surface of the ear canal of the user, and therefore alleviates the above mentioned problems, while at the same time providing the advantages of increased sound amplification discussed above.
The ear canal of a human consists basically of two parts, namely an outer cartilaginous part and an inner bony part. The cartilaginous part of the ear canal is very dynamic and moves considerably together with the mandible bone, when a person moves his or her jaw, for example when smiling, chewing or talking. With the customized tip part, there will be less transmission of movements from the outer cartilaginous part of the ear canal toward the inner bony part that is very touch-sensitive.
The custom tip is preferable manufactured by a standard rapid prototyping process, such as selective laser sintering (SLS) process, stereolithography (SLA) process, etc.
In order to reduce occlusion, a so-called vent, i.e. a ventilation channel, may be provided in the customized tip part for communication between the surroundings and the ear canal volume behind the sealing tip part in the ear canal. The vent may be drilled through the tip part, or a pipe or tube extending within the tip part may constitute the vent. The effectiveness of the vent is increased by increasing the cross-section and decreasing the length of the vent channel. Because of the passageway between the ear canal wall and the trunk part of the housing, the vent is very short and very effective.
Provision of a customized hearing instrument housing by provision of a customized tip part and a standard sized trunk part decreases the manufacturing cost compared to conventional customized hearing instrument housings.
In one embodiment, a custom made part is provided fitting around a standard sized tip part for individually fitting a standard sized housing to a specific user's ear canal.
In one embodiment, a flexible part fitting around a standard sized tip part is provided for improved fitting of the housing to a specific user's ear canal. The flexible part may be provided in a number of standard sizes.
The hearing instrument may further comprise a cerumen filter that is adapted to be fitted on the receiver or on the tip part of the housing with a snap on coupling.
In a preferred embodiment, the set of hearing instrument housing parts comprises one standard sized trunk part fitting a large majority of possible users, however, the set of hearing instrument housing parts may further comprise a plurality of differently sized trunk parts.
The set of hearing instrument housing parts may further comprise a plurality of differently sized receivers.
The set of hearing instrument housing parts may further comprise a plurality of differently sized elongate members.
Thus, typically, a hearing instrument housing for the right ear of a specific user is assembled, e.g. at the point of sale of the hearing instrument, from parts selected for provision of a best fit with the right ear pinna and the right ear canal of the user in question by selection of an appropriately sized trunk part for connection with a right ear connector having the elongate member at an angle suitable for use in the right ear of the user. Further, the selected trunk part may be interconnected with a selected right tip part that forms an angle towards the left in relation to the longitudinal extension of the trunk part when seen from above in the medial direction of the ear canal facilitating accommodation in the right ear canal of the user in question. A hearing instrument housing for the left ear of a specific user is assembled in a similar way.
Preferably, the receiver is accommodated in the tip part of the housing.
The trunk part of the housing may comprise a connector for making mechanical and electrical contact with the receiver. In this way, the receiver may be installed in the hearing instrument housing at the point of sale, e.g. by the dispenser so that the dispenser may be able to offer a variety of models to the user without a need for purchasing and storing a similar variety of hearing instruments.
Preferably, the trunk part accommodates the signal processor of the hearing instrument for generating an audio signal.
The hearing instrument may further comprise a battery or batteries for power supply of the electric components of the hearing instrument. The battery or batteries may be rechargeable or non-rechargeable.
The size and shape of the housing according to some embodiments has proven to be so comfortable that users are able to sleep well with the housing inserted in an ear canal. This makes the housing well suited for use in tinnitus relieving and noise suppression.
In an embodiment, the hearing instrument constitutes a hearing aid comprising a microphone for converting sound into an audio signal, a signal processor for processing the audio signal for compensating a hearing loss, and a loudspeaker that is connected to an output of the signal processor for converting the processed audio signal into a sound signal. Further, the hearing aid comprises a battery for power supply of the electric components of the hearing aid.
In accordance with hearing aid terminology, the loudspeaker is also denoted a receiver throughout the present specification.
The hearing instrument housing may accommodate the above-mentioned hearing aid components including the microphone in a way similar to the housing of a CIC hearing aid.
In an embodiment, the elongate member accommodates the microphone, e.g. at its second end, and the remaining part or parts of the housing accommodate the other components, and signal conductors extend within the elongate member for electrical interconnection of the microphone with other components in the housing.
In a preferred embodiment, electronic feedback compensation is provided. Feedback is a well-known problem in hearing instruments and several systems for suppression and cancellation of feedback exist within the art. With the development of very small digital signal processing (DSP) units, it has become possible to perform advanced algorithms for feedback suppression in a tiny device, such as a hearing aid, see e.g. U.S. Pat. No. 5,619,580, U.S. Pat. No. 5,680,467 and U.S. Pat. No. 6,498,858.
The above mentioned prior art systems for feedback cancellation in hearing aids deal with external feedback, i.e. transmission of sound between the loudspeaker (often denoted receiver) and the microphone of the hearing aid along a path outside the hearing aid device. This problem, which is also known as acoustical feedback, occurs e.g. when a hearing aid earpiece part does not completely fit the users ear, or in the case of an earpiece part comprising a vent. In both examples, sound may “leak” from the receiver to the microphone and thereby cause feedback.
The problem of external feedback limits the maximum gain available in a hearing aid.
Thus, the hearing aid may further comprise a feedback compensation circuit for providing a feedback compensation signal of signals picked up by the microphone by modelling an acoustical and mechanical feedback signal path of the hearing aid, subtracting means for subtracting the feedback compensation signals from the audio signal to form a compensated audio signal, which is input to the signal processor of the hearing aid.
The feedback signal path is typically an acoustic path between the microphone and the receiver, i.e. an external feedback signal propagates through air surrounding the hearing aid.
Preferably, the feedback compensation means comprises an adaptive filter, i.e. a filter that changes its impulse response in accordance with changes in the feedback path.
Both static and adaptive filters are well known to a person skilled in the art of hearing aids, and will therefore not be discussed in further detail here.
Tinnitus is the perception of sound in the human ear in the absence of corresponding external sound(s). Tinnitus is considered a phantom sound, which arises in the auditory system. For example, a ringing, buzzing, whistling, or roaring sound may be perceived as tinnitus. Tinnitus can be continuous or intermittent, and in either case can be very disturbing, and can significantly decrease the quality of life for one who has such an affliction.
Tinnitus is not itself a disease but an unwelcome symptom resulting from a range of underlying causes, including psychological factors such as stress, disease (infections, Menieres Disease, Oto-Sclerosis, etc.), foreign objects or wax in the ear and injury from loud noises. Tinnitus is also a side-effect of some medications, and may also result from an abnormal level of anxiety and depression.
The perceived tinnitus sound may range from a quiet background sound to a signal loud enough to drown out all outside sounds. The term ‘tinnitus’ usually refers to more severe cases. A 1953 study of 80 tinnitus-free university students placed in a soundproofed room found that 93% reported hearing a buzzing, pulsing or whistling sound. However, it must not be assumed that this condition is normal—cohort studies have demonstrated that damage to hearing from unnatural levels of noise exposure is very widespread.
Tinnitus cannot be surgically corrected and since, to date, there are no approved effective drug treatments, so-called tinnitus maskers have become known. These are small, battery-driven devices which are worn like a hearing aid behind or in the ear and which, by means of artificial sounds which are emitted, for example via a hearing aid speaker into the auditory canal, to thereby psycho acoustically mask the tinnitus and thus reduce the tinnitus perception.
The artificial sounds produced by the maskers are often narrow-band noise. The spectral position and the loudness level of the noise can often be adjusted via for example a programming device to enable adaptation to the individual tinnitus situation as optimally as possible. In addition, so-called retraining methods have been developed, for example tinnitus retraining therapy (Jastreboff P J. Tinnitus habituation therapy (THI) and tinnitus retraining therapy (TRT). In: Tyler R S, ed. Handbook of Tinnitus. San Diego: Singular Publishing; 2000:357-376) in which, by combination of a mental training program and presentation of broad-band sound (noise) near the auditory threshold, the perceptibility of the tinnitus in quiet conditions is likewise supposed to be largely suppressed. These devices are also called “noisers” or “sound enrichment devices”. Such devices or methods are for example known from DE 29718 503, GB 2 134 689, US 2001/0051776, US 2004/0131200 and U.S. Pat. No. 5,403,262.
Although present day tinnitus maskers to a certain extent may provide immediate relief of tinnitus, the masking sound produced by them may adversely affect the understanding of speech, partly because S/N (Speech/Noise) ratio would be lower due to the addition of noise, and partly because persons suffering from tinnitus often also suffer from a reduced ability to understand speech in noise as compared to people with normal hearing.
For many people, the known maskers will not provide any long term relief of tinnitus. Recent research conducted by Del Bo, Ambrosetti, Bettinelli, Domenichetti, Fagnani, and Scotti “Using Open-Ear Hearing Aids in Tinnitus Therapy”, Hearing Review, August 2006, has indicated that better long term effects for tinnitus relief may be achieved if so-called habituation of tinnitus is induced in a tinnitus sufferer by using sound enrichment by sound from the ambient environment. The rationale behind habituation relies on two fundamental aspects of brain functioning: Habituation of the reaction of the limbic and sympathetic system, and habituation of sound perception allowing a person to ignore the presence of tinnitus. While tinnitus maskers emit sounds that either partly or completely cover the perceived sound of tinnitus, Del Bo, Ambrosetti, Bettinelli, Domenichetti, Fagnani, and Scotti suggest the use of environmental sounds amplified by a hearing aid or by application of artificial sounds, such as band limited noise. According to an aspect of some embodiments, the hearing instrument also includes a tinnitus relieving circuit, for example generating sounds useful for relieving tinnitus as described above. The relieving circuit may for example be a tinnitus masker, a sound enrichment circuit, etc.
According to another aspect of some embodiments, a tinnitus relieving device or a tinnitus therapy device is provided with a housing and an elongate member as disclosed throughout the present disclosure. The tinnitus relieving device may not have a microphone. In one embodiment, the tinnitus relieving device does not compensate for a hearing loss.
In another embodiment, a hearing instrument includes a tinnitus relieving device or a tinnitus therapy device.
According to yet another aspect of some embodiments, a noise suppression device is provided with a housing and an elongate member as disclosed throughout the present disclosure. The noise suppression device may not have a microphone. In one embodiment, the noise suppression device does not compensate for a hearing loss.
In another embodiment, a hearing instrument includes a noise suppression device.
The noise suppression device may have a conventional noise suppression circuit with a signal processor for performing analysis of the waveform of the background aural or non-aural noise, and generation of a polarisation reversed waveform to cancel the background noise out by interference. The generated waveform has identical or directly proportional amplitude to the waveform of the original noise, but its polarity is reversed. This creates the destructive interference that reduces the amplitude of the perceived noise.
In accordance with some embodiments, a set of hearing instrument parts includes a trunk part shaped for accommodation in a right ear canal or a left ear canal of a user, an elongate member having a first end and a second free end, a left ear connector configured to be attached to the trunk part and to be attached to the first end of the elongate member, wherein when the left ear connector is attached to the trunk part and the first end of the elongate member, the elongate member forms a first angle with a longitudinal extension of the trunk part, the first angle being suitable for a left ear of the user, and a right ear connector configured to be attached to the trunk part and to be attached to the first end of the elongate member, wherein when the right ear connector is attached to the trunk part and the first end of the elongate member, the elongate member forms a second angle with a longitudinal extension of the trunk part, the second angle being suitable for a right ear of the user, wherein the elongate member is configured for connection with a selected one of the left ear connector and the right ear connector, and for positioning in a pinna for retention of the trunk part in the left ear canal or the right ear canal.
In accordance with other embodiments, a set of hearing instrument parts includes a trunk part that is selectively placeable in a left ear canal or a right ear canal or a user, an elongate member having a first end and a second free end, a left ear connector configured to connect the trunk part and the elongate member to form a first configuration that is suitable for a left ear of the user, and a right ear connector configured to connect the trunk part and the elongate member to form a second configuration that is suitable for a right ear of the user, wherein the elongate member is configured for placement in a pinna for retention of the trunk part in a selected one of the left ear canal and the right ear canal.